D1.2 REPORT ON MOTORCYCLISTS IMPACTS WITH ROAD INFRASTRUCTURE BASED OF AN INDEPTH INVESTIGATION OF MOTORCYCLE ACCIDENTS

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1 WP 1 D1.2 REPORT ON MOTORCYCLISTS IMPACTS WITH ROAD INFRASTRUCTURE BASED OF AN INDEPTH INVESTIGATION OF MOTORCYCLE ACCIDENTS Project Acronym: Smart RRS Project Full Title: Innovative Concepts for smart road restraint systems to provide greater safety for vulnerable road users. Grant Agreement No.: Responsible: Università degli Studi di Firenze Internal Quality Reviewer: Centro Zaragoza

2 SUMMARY: The objective of the Innovative concepts for smart road restraint systems to provide greater safety for vulnerable road users (Smart RRS) project is to reduce the number of injuries and deaths caused by road traffic accidents to vulnerable road users such as motorcyclists, cyclists and passengers through the development of a smart road restraint system. Within the WP1 Characteristics of severe road traffic accidents concerning vulnerable road users such as motorcyclists the task 1.2, In depth Motorcycle Accident Investigation, aims at identifying the specific characteristics of motorcycle accidents where motorcyclists impact with road infrastructure (poles, signals, barriers, etc.). Moreover, it also intends to define the main parameters of these accidents (kinematics, injured body regions, etc), based on an indepth investigation of a wide sample of motorcycle accidents, and establish the basis for assessing the effectiveness of new protection devices, taking into account real life conditions. A total of 239 accidents from three different in-depth databases have been collected and analysed. The selection criteria for the accidents was: At least one motorcycle involved. The motorcyclist collided with any element of the road infrastructure (poles, signals, barriers, etc). The main findings can be summarised as follow: PTW kinematics and surrounding conditions Fatal (serious) accidents & PTW impact against a Guardrail barrier/posts fencing In the majority of accidents the PTW's speed > 70 (> 50) km/h, the roll angle is 0 ( 0), the sideslip angle is little and the first part of PTW involved in the accidents is the front or the centre. Regarding the surround and environmental conditions in the majority of accidents the road is curve left, the road do not present defects, the accident occurred with traffic, there are not visibility limitation, the roadside is not contaminated (in 53% of the cases the roadside is contaminated) and in the end the weather is clear. PTW kinematics and surrounding conditions Fatal (serious) accidents & PTW impact against a Building structures/embankment/tree/ditch or low lying depression In the majority of accidents the PTW s speed is > 50 (< 70) km/h, the roll angle = 0, the sideslip angle is little and the first part of PTW involved in the accidents is the front or the centre. Regarding the surround and environmental condition, the 45% of the accidents occurred in a straight road (majority in a curve); moreover for the majority of accidents the road do not present defects, the accident occurred in a light or absent traffic conditions, there aren t visibility, the roadside is not contaminated and in the end the weather is clear (in the 53% is not clear). 2

3 PTW riders kinematics Fatal (serious) accidents & impact against a Guardrail barrier/posts fencing All (43%) the riders have a speed at impact > 70 km/h. 41% (all) of the riders slide on the pavement. 60% of the riders have an impact angle, < % of the riders have an angle > % (7%) of the riders impact on the barrier post. 21% (14%) of the riders impact on the rail of barrier. PTW riders kinematics Fatal (serious) accidents & impact against a structures/embankment/tree/ditch or low lying depression 50% of the riders have a speed at impact between 50 and 70 (< 50) km/h. 90% (33%) of the riders do not slide on the pavement. 3

4 INDEX SUMMARY: Aim of the study UNIFI: in-depth motorcycle accident investigation Introduction Methodology PTW accidents summary characteristic Data analysis Roadside & features of PTW kinematics of accident PTW impact speed PTW roll attitude angle at impact PTW sideslip angle at impact PTW first collision contact code Roadside & features of PTW rider kinematic of PTW rider number of impacts Roadside & features of roadside alignment Roadside horizontal alignment Roadside infrastructure & accident causation Roadside condition and defects Traffic control on path of travel visibility Traffic density at the time of accident Visibility limitation Stationary view obstructions along the rider s line of sight at the time of precipitating event Mobile view obstructions along the rider s line of sight at the time of the precipitating event Weather description Roadside contamination Roadside infrastructures & consequences Trauma status Head injury due to impact with the Upper extremities injury due to impact with the Thorax injury due to impact with the Spine injury due to impact with the Abdomen injury due to impact with the Lower extremities injury due to impact with the Whole body injury due to impact with the Personal protective equipment Wearing helmet on head Was helmet retained in place on head during accident? Type of helmet PTW fatal rider injuries: Wearing helmet on head? PTW fatal rider injuries: Body coverage material Body coverage material & upper extremities AIS Body coverage material & Thorax AIS Body coverage material & lower extremities AIS Footwear material/type & lower extremities AIS

5 Body coverage material & Whole body AIS Relationship between features of PTW kinematics PTW impact speed & PTW roll attitude angle at impact Conclusions Centro Zaragoza: in-depth motorcycle accident investigation PTW accidents summary characteristic Data analysis Roadside & features of PTW kinematics of accident PTW impact speed PTW roll attitude angle at impact PTW sideslip angle at impact PTW first collision contact code Roadside & features of PTW rider kinematic of PTW rider speed at impact PTW rider impact angle PTW rider impact speed & PTW rider impact angle PTW rider sliding on back/front? PTW rider impact orientation with respect to road tangent PTW rider impact on barrier post? PTW rider impact on rail of barrier? PTW rider number of impacts Rider motion (post crash) Roadside & features of roadside alignment Roadway horizontal alignment Roadside infrastructure & accident causation Roadside condition and defects Traffic control on path of travel is visible to PTW rider? Traffic density at time of accident PTW rider visibility limitation due to Stationary view obstructions along the rider s line of sight at the time of precipitating event Mobile view obstructions along the rider s line of sight at time of precipitating event Weather description Roadside contamination Roadside infrastructures & consequences PTW rider trauma status Head injury due to impact with the Upper extremities injuries due to impact with the Thorax injuries due to impact with the Spine injuries due to impact with the Abdomen injuries due to impact with the Lower extremities injuries due to impact with the Whole body injuries due to impact with the Personal protective equipment Wearing helmet on head & Head AIS Was helmet retained in place on head during accidents? Type of helmet & Head AIS

6 Fatal riders: wearing helmet on head? Body coverage material Body coverage material & upper extremities AIS Body coverage material & Thorax AIS Body coverage material & Spine AIS Body coverage material & abdomen AIS Body coverage material & lower extremities AIS Body coverage material & whole body AIS Relation between the features of the PTW kinematics PTW impact speed & PTW roll attitude angle at impact Conclusions Applus IDIADA: in-depth motorcycle accident investigations PTW accidents summary characteristic Data analysis Roadside & features of PTW kinematics of accident PTW impact speed PTW roll attitude angle at impact PTW sideslip angle at impact PTW first collision contact Roadside & features of PTW rider kinematic PTW rider speed at impact PTW rider impact angle PTW rider impact speed & PTW rider impact angle PTW rider sliding on back/front? PTW rider impact orientation with respect to road tangent PTW rider impact on barrier post? PTW rider impact on rail of barrier? PTW rider number of impacts Rider motion (post crash) Roadside & features of roadside alignment Roadway horizontal alignment Roadside infrastructure & accident causation Condition and defects Traffic control on path of travel visibility Traffic density at time of accident Visibility limitation Stationary view obstructions along the rider s line of sight at the time of precipitating event Mobile view obstructions along the rider s line of sight at the time of precipitating event Weather description Roadside contamination Roadside infrastructures & consequences Trauma status Head injuries due to impact with the Personal protective equipment Wearing helmet on head & head AIS

7 Was helmet retainded in place on head during accidents? & Head AIS Type of helmet & Head AIS Wearing helmet on head? & Roadside & body coverage material Relation between the features of the PTW kinematics PTW impact speed & PTW roll attitude angle at impact Conclusions Comparison between the different databases and summary Information Number of cases and motorcycle motor displacement Data analysis Roadside & features of PTW kinematics of accidents PTW impact speed PTW Roll attitude angle at impact PTW sideslip angle at impact PTW first collision contact code Roadside & features of PTW rider kinematics of accidents PTW rider number of impacts PTW rider speed at impacts PTW rider impact angle PTW rider impact speed & PTW rider impact angle PTW rider sliding on back/front? PTW rider impact orientation with respect to road tangent PTW rider impact on barrier post? PTW rider impact on rail of barrier? Rider motion post crash Roadside & features of roadside alignment Roadway horizontal alignment Roadside infrastructures & accidents causation Roadside condition and defects Traffic density at the time of accidents Visibility limitation due to Roadside & stationary view obstructions along the rider s line of sight at the time of precipitating event Roadside & mobile view obstructions along the rider s line of sight at the time of precipitating event Weather description Roadside contamination Roadside infrastructures & consequences Trauma status Head injuries due to impact with the Upper extremities injuries due to impact with the Thorax injuries due to impact with the Spine injuries due to impact with the Abdomen injuries due to impact with the Lower extremities injuries due to impact with the Personal protective equipment

8 Was helmet retained in place on head during accident? Body coverage material & upper extremities AIS Body coverage material & thorax AIS Conclusion Summary information

9 1 Aim of the study This in-depth accident investigation has the objective to make a snapshot of the moment of the accident, in which either only one vehicle, the PTW (motorcycle or moped) is involved, or more vehicles are involved (one of them should be a PTW), without impact between the moving vehicles. We have focussed our attention especially on the impact against Guardrail barrier / Posts fencing. We have analyzed the accidents with regard to the PTW and rider kinematics, roadside infrastructure and surrounding conditions, trauma suffered by the riders and the effectiveness of the body coverage material. The analysis has considered real accidents provided by three In-deph accidents databases : MAIDS (by ACEM), CENTRO ZARAGOZA, APPLUS IDIADA for a total of 239 accidents. 2 UNIFI: in-depth motorcycle accident investigation 2.1 Introduction The study has investigated the features of the PTW accidents focusing the motorcycle and rider kinematics, roadside and weather conditions, single body part injuries analysis and the effectivity of the body coverage materials. These information have been collected with an in-depth accidents investigation on a sample of PTW accidents. We have based our analysis on the MAIDS database realized by ACEM (Association of European Motorcycle Manufacturers) with the support of the European Commission and other partners during the period in five sampling areas located in France, Germany, Netherlands, Spain and Italy. The database collected 921 motorcycle accidents, which were investigated in detail resulting in approximately 2000 variables for each accident, and 923 controllers, which provided comparative information on riders and PTWs that were not involved in accidents in the same sample areas. These information on accidents were collected with the (OECD) methodology for on-scene in-depth motorcycle accident investigations: the methodology developed by the Organisation for Economic Co-operation and Development was used by all five research groups in order to maintain consistency in the data collected in each sampling area. 2.2 Methodology In our analysis we have considered, from the MAIDS database, the accidents where only one vehicle, the PTW (motorcycle or moped), is involved and those involving more vehicles (one of these should be a PTW), without impact between moving vehicles. Our sample has accounted for 193 accidents that we have investigated respect the different features of accidents. All the injuries in the analysis are concerned PTW riders. In the analysis of PTW and rider kinematics and for the roadside condition we have analysed the different variables respect to a three levels scale of accident severity: slight injuries (AIS 1 or 2), serious injuries (AIS 3+) and fatal injuries; whereas for the body parts injuries analysis and for the protective equipments analysis we have reported the severity of injuries with a single value of the AIS scale. The riders impact have been grouped in three subcategories, Guardrail barrier/ Posts fencing - structures / embankment / tree(small plants, vegetation) - Parked vehicles / other unknown, according to the aim of the study and to obtain categories with a significative number of data. In the analysis of the singular parameters, which characterize the accidents, we have arranged the data in the crosstable form; for each configuration we have provided the statistical tests like the Pearson Chi-square, Fisher s exact test (and depending on the expected counts and the type of variables, nominal or ordinal, we have considered the right test) in order to assess the statistical significance of relationship whereas for the strength of association we have reported the Cramer s V and other specific tests depending on the type of data. 9

10 2.3 PTW accidents summary characteristic Table. 1 Summary information Number of accidents and fatal accidents by motor displacement n of accidents n of fatal accidents counts % on total moped 49 25,4 motorcycle ,6 total ,0 moped 5 17,2 motorcycle 24 82,8 total ,0 This table (Table. 1) is helpful to know the summary information respect to the composition of our sample: concern to the motor displacement, and the fatality of the accidents. How we can see the highest percentage of PTWs, involved in accidents, were motorcycle (74,6%) whereas the moped accounted for about the 25% of accidents. In general, every one hundred of accidents there are 15 dead riders: the majority (82,8%) drove a motorcycle whereas the 17,2% drove a moped. Table. 2 Summary information Number of accidents related to: roadside obstacle & severity of the accidents Roadside Guardrail barrier/posts fencing structures/embankment/tree Parked vehicles/other unknown Severity of the accidents Fatal Serious Slight count row % 43,8% 31,3% 25,0% 100,0% count row % 8,7% 11,5% 79,8% 100,0% count row % 10,5% 26,3% 63,2% 100,0% count row % 15,0% 19,2% 65,8% 100,0% In Table. 2 we can see that the accidents for which the riders impacted against a Guardrail barrier/posts fencing have a higher fatality (43,8%) respect to the accidents for which the impact happened with the other types of the. 10

11 2.4 Data analysis Roadside & features of PTW kinematics of accident In the first step of the analysis we have considered several of the principal features of the PTW kinematics at the time of the accident, starting with the PTW impact speed. In the following crosstables we have grouped together the information concerning the L1 and L3 motorcycle legal category PTW impact speed Table. 3 Number of accidents, by severity, related to: ROADSIDE OBSTACLES & PTW IMPACT SPEED PTW Impact Speed categories [km/h] severity of the accidents slight Guardrail barrier/posts injuries fencing serious injuries fatal structures/embankment/tree Parked vehicles/other unknown unknown Count row % 62,5% 37,5% Count row % 71,1% 12,0% 14,5% 2,4% Count row % 66,7% 13,9% 19,4% Count Guardrail barrier/posts fencing structures/embankment/tree Parked vehicles/other unknown row % 69,3% 11,8% 17,3% 1,6% 100,0% Count row % 40,0% 50,0% 10,0% Count row % 50,0% 50,0% Count row % 40,0% 13,3% 46,7% Count Guardrail barrier/posts fencing structures/embankment/tree Parked vehicles/other unknown row % 43,2% 35,1% 21,6% 100,0% Count row % 14,3% 21,4% 64,3% Count row % 55,6% 44,4% Count row % 50,0% 50,0% Count row % 17,2% 37,9% 44,8% 100,0% In the Table.3 we have analyzed the PTW impact speed versus the different types of the within the three categories of the accidents severity. Moving from the slight injuries to the fatal injuries, we see that the percentage concentration of accidents, with a PTW impact speed over the 70 km/h, shifts from 17,3% to 44,8%. 11

12 Especially for the Guardrail barrier/posts fencing obstacle the speed category with the highest percentage of cases accounting for about the 60% of accidents: this figure for slight injuries is represented by the 0-50 speed band whereas for fatal injuries is represented by the > 70 band. For the structures-embankment-tree we notice the same percentage movement of Guardrail barrier/posts fencing if we pass from the slight injuries to the fatal injuries. From the described data, appear a clear relationship between the impact speed and the severity of the accident; in the Table.3A we have put in relationship the two variables in order to assess the presence of a statistical significative relationship. How we can see from the Chi-Square Tests table, especially from the linear-by-linear association (23,181),there is a significative relationship between the two variables (p-value 0,000) and a moderate association (Kendall's tau-b,335). Table. 3A Number of accidents* related to: SEVERITY OF THE ACCIDENTS & PTW IMPACT SPEED severity of the accidents slight injuries serious injuries PTW Impact Speed categories [km/h] Count row % 70,4% 12,0% 17,6% 100,0% Count row % 43,2% 35,1% 21,6% 100,0% Fatal Count row % 17,2% 37,9% 44,8% 100,0% Count *accidents with a known PTW impact speed row % 57,1% 20,4% 22,5% 100,0% Chi-Square Tests (for the Table 3A) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Value df Point Probability Pearson Chi-Square 33,579 a 4,000,000 Likelihood Ratio 34,322 4,000,000 Fisher's Exact Test 34,196,000 Linear-by-Linear Association 23,181 b 1,000,000,000,000 N of Valid Cases 191 a. 0 cells (,0%) have expected count less than 5. The minimum expected count is 5,92. b. The standardized statistic is 4,

13 Symmetric Measures (for the Table 3A) Value Asymp. Std. Error a Approx. T b Approx. Sig. Exact Sig. Nominal by Nominal Phi,419,000,000 Cramer's V,296,000,000 Ordinal by Ordinal Kendall's tau-b,335,063 5,087,000,000 Kendall's tau-c,274,054 5,087,000,000 N of Valid Cases 191 a. Not assuming the null hypothesis. b. Using the asymptotic standard error assuming the null hypothesis. In the Table.3B we have put in relationship the and the PTW impact speed regardless of the severity of the accidents. The PTW impact speed, when the roadside obstacle is Guardrail barrier/posts fencing, is higher than for other which have more than the fifty percent of cases in the speed band 0-50 km/h. The relationship between the variables is significative (Pearson Chi-Square 11,128 p- value=0,025) and the strength of the association is 0,171. Table. 3B Number of accidents* related to: ROADSIDE OBSTACLES & PTW IMPACT SPEED PTW Impact Speed categories [km/h] Roadside Guardrail barrier/posts fencing Count row % 34,4% 25,0% 40,6% 100,0% structures/embankment/tree Count row % 63,7% 20,6% 15,7% 100,0% Parked vehicles/other unknown Count row % 57,9% 17,5% 24,6% 100,0% Count *accidents with a known PTW impact speed row % 57,1% 20,4% 22,5% 100,0% 13

14 Chi-Square Tests (for the Table 3B) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 11,128 a 4,025,024 Likelihood Ratio 10,916 4,028,031 Fisher's Exact Test 10,993,025 Linear-by-Linear Association 2,621 b 1,105,116,060,014 N of Valid Cases 191 a. 0 cells (,0%) have expected count less than 5. The minimum expected count is 6,53. b. The standardized statistic is -1,619. Symmetric Measures (for the Table 3B) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,241,025,024 Cramer's V,171,025,024 N of Valid Cases

15 PTW roll attitude angle at impact Table. 4 Number of accidents, by severity, related to: ROADSIDE OBSTACLES & PTW ROLL ATTITUDE ANGLE AT IMPACT PTW roll attitude angle at impact [deg] severity of the accidents unknown slight Guardrail barrier/posts fencing Count injuries row % 50,0% 25,0% 12,5% 12,5% 100,0% serious injuries fatal structures/embankment/tree Count row % 28,9% 16,9% 45,8% 8,4% 100,0% Parked vehicles/other unknown Count row % 16,7% 50,0% 30,6% 2,8% 100,0% Count row % 26,8% 26,8% 39,4% 7,1% 100,0% Guardrail barrier/posts fencing Count structures/embankment/tree row % 20,0% 40,0% 40,0% 100,0% Count row % 16,7% 16,7% 66,7% 100,0% Parked vehicles/other unknown Count row % 46,7% 20,0% 26,7% 6,7% 100,0% Count row % 29,7% 24,3% 43,2% 2,7% 100,0% Guardrail barrier/posts fencing Count structures/embankment/tree row % 28,6% 7,1% 57,1% 7,1% 100,0% Count row % 33,3% 33,3% 22,2% 11,1% 100,0% Parked vehicles/other unknown Count row % 50,0% 33,3% 16,7% 100,0% Count row % 24,1% 24,1% 41,4% 10,3% 100,0% From the marginal row (Table. 4), of each modality of the accidents severity, we can see that the roll angle band with the highest percentage of cases is the category which comprises the angles between one and ninety degree. Inside the fatal injuries we find some differences between the : for the Guardrail barrier/posts fencing the 57,1% of accidents have a positive PTW impact angle and only the 7,1% have happened in upright position; instead for the structures/embankment/tree the highest percentages (33,3%) are referred to the upright position and to the negative roll angles. For serious injuries, when the is Guardrail barrier/posts fencing, there are 40% of cases both for the positive roll angles and for the upright position; with structures/embankment/tree in the 66,7% of cases there is a positive roll angle of the PTW. 15

16 Table. 4A Number of accidents* related to: SEVERITY OF THE ACCIDENTS & PTW ROLL ATTITUDE ANGLE AT IMPACT PTW roll attitude angle at impact [deg] severity of the accidents slight injuries Count row % 28,8% 28,8% 42,4% 100,0% serious injuries Count row % 30,6% 25,0% 44,4% 100,0% fatal Count row % 26,9% 26,9% 46,2% 100,0% Count *accidents with a known PTW roll attitude angle at impact row % 28,9% 27,8% 43,3% 100,0% In Table 4A we have put in relationship the severity of the accident with the PTW roll attitude angle at impact. if we look the Pearson Chi-Square (0,305) test we don t find a significative relationship between the variables. Chi-Square Tests (for the Table 4A) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square,305 a 4,989,990 Likelihood Ratio,307 4,989,990 Fisher's Exact Test,355,992 Linear-by-Linear Association,077 b 1,782,810,416,046 N of Valid Cases 180 a. 0 cells (,0%) have expected count less than 5. The minimum expected count is 7,22. b. The standardized statistic is,277. Symmetric Measures (for the Table 4A) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,041,989,990 Cramer's V,029,989,990 N of Valid Cases

17 Table. 4B Number of accidents* related to: ROADSIDE OBSTACLES & PTW ROLL ATTITUDE ANGLE AT IMPACT PTW roll attitude angle at impact [deg] Roadside Guardrail barrier/posts fencing Count structures/embankment/tree row % 33,3% 23,3% 43,3% 100,0% Count row % 30,2% 19,8% 50,0% 100,0% Parked vehicles/other unknown Count row % 24,1% 44,4% 31,5% 100,0% Count *accidents with a known PTW roll attitude angle at impact row % 28,9% 27,8% 43,3% 100,0% The relationship between Roadside and PTW roll attitude angle at impact (Table. 4B) is statistical significative: the Pearson Chi-Square is 11,249, p-value=0,024 and the Cramer s V is equal to 0,177. Chi-Square Tests (for the Table 4B) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 11,249 a 4,024,023 Likelihood Ratio 10,824 4,029,032 Fisher's Exact Test 10,692,029 Linear-by-Linear Association,107 b 1,744,792,398,050 N of Valid Cases 180 a. 0 cells (,0%) have expected count less than 5. The minimum expected count is 8,33. b. The standardized statistic is -,327. Symmetric Measures (for the Table 4B) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,250,024,023 Cramer's V,177,024,023 N of Valid Cases

18 PTW sideslip angle at impact Table. 5 Number of accidents, by severity, related to: ROADSIDE OBSTACLES & PTW SIDESLIP ANGLE AT IMPACT severity of the accidents slight injuries serious injuries fatal Guardrail barrier/ Posts fencing structures/ embankment/tree Parked vehicles/ other unknown Guardrail barrier/ Posts fencing structures/ embankment/tree Parked vehicles/ other unknown Guardrail barrier/ Posts fencing structures/ embankment/tree Parked vehicles/ other unknown PTW Sideslip angle at impact [deg] Count unknown row % 37,5% 62,5% 100,0% Count row % 1,2% 1,2% 63,9% 3,6% 3,6% 2,4% 24,1% 100,0% Count row % 83,3% 2,8% 13,9% 100,0% Count row %,8%,8% 67,7% 3,1% 2,4% 1,6% 23,6% 100,0% Count row % 70,0% 10,0% 20,0% 100,0% Count row % 8,3% 66,7% 25,0% 100,0% Count row % 86,7% 13,3% 100,0% Count row % 2,7% 75,7% 2,7% 18,9% 100,0% Count row % 7,1% 42,9% 7,1% 42,9% 100,0% Count row % 11,1% 11,1% 55,6% 22,2% 100,0% Count row % 83,3% 16,7% 100,0% Count row % 3,4% 3,4% 3,4% 55,2% 3,4% 31,0% 100,0% All the accidents (Table. 5) are characterized by a PTW sideslip angle at impact in the range from -50 to 50 degree. On the whole the angle category with the highest percentage of cases is If we consider accidents with a known angle (Table. 5A), grouped in three category, we can see that the category (-10,10 ) gathers about the 90% of the cases. The relationship between the severity of the accident and the PTW sideslip angle at impact is no statistical significative (Table. 5A): the Fisher's Exact Test is 3,996 (Exact sig. 0,340). 18

19 Table. 5A Number of accidents* related to: SEVERITY OF THE ACCIDENTS & PTW SIDESLIP ANGLE AT IMPACT PTW Sideslip angle at impact [deg] severity of the accidents , slight injuries Count row % 2,1% 88,7% 9,3% 100,0% serious injuries Count row % 3,3% 93,3% 3,3% 100,0% fatal Count row % 10,0% 85,0% 5,0% 100,0% Count *accidents with a known PTW sideslip angle at impact row % 3,4% 89,1% 7,5% 100,0% Chi-Square Tests (for the Table 5A) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 4,445 a 4,349,333 Likelihood Ratio 3,818 4,431,554 Fisher's Exact Test 3,996,340 Linear-by-Linear Association 3,472 b 1,062,061,048,014 N of Valid Cases 147 a. 5 cells (55,6%) have expected count less than 5. The minimum expected count is,68. b. The standardized statistic is -1,863. Symmetric Measures (for the Table 5A) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,174,349,333 Cramer's V,123,349,333 N of Valid Cases

20 Table. 5B Number of accidents* related to: ROADSIDE OBSTACLES & PTW SIDESLIP ANGLE AT IMPACT PTW Sideslip angle at impact [deg] , Roadside Guardrail barrier/posts fencing Count structures/embankment/tree row % 5,3% 84,2% 10,5% 100,0% Count row % 5,1% 84,8% 10,1% 100,0% Parked vehicles/other unknown Count row % 98,0% 2,0% 100,0% Count *accidents with a known PTW sideslip angle at impact row % 3,4% 89,1% 7,5% 100,0% The relationship, in table 5B, between the and the PTW sideslip angle at impact, regardless the severity of the accident, is no statistical significative (Fisher's Exact Test 6,540 p-value=0,113). Nevertheless for the Guardrail barrier/posts fencing and the structures/embankment/tree we find a very similar distribution of the frequencies (Table.5B) between the PTW sideslip angle categories: about the 84% of cases are gathered in the central interval and for the other we find the double of cases in positive angle band respect to the negative angle band. Chi-Square Tests (for the Table 5B) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 6,060 a 4,195,184 Likelihood Ratio 8,299 4,081,113 Fisher's Exact Test 6,540,113 Linear-by-Linear Association,335 b 1,563,612,316,068 N of Valid Cases 147 a. 5 cells (55,6%) have expected count less than 5. The minimum expected count is,65. b. The standardized statistic is,

21 Symmetric Measures (for the Table 5B) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,203,195,184 Cramer's V,144,195,184 N of Valid Cases 147 Table. 5C Number of accidents* related to: ROADSIDE OBSTACLES & PTW SIDESLIP ANGLE AT IMPACT** PTW Sideslip angle at impact [deg] Roadside Guardrail barrier/ Posts fencing Count row % 84,2% 15,8% 100,0% structures/embankment/tree Count row % 84,8% 15,2% 100,0% Parked vehicles/ other unknown Count row % 98,0% 2,0% 100,0% Count * accidents with a known PTW sideslip angle at impact ** we have considered in this table the absolute value of the angle row % 89,1% 10,9% 100,0% In Table 5C we have considered the wideness of the angle ignoring if it is positive or negative. By the Chi-Square Tests (5,932) we see that there is a quite close significative relationship between the and the wideness of the sideslip angle; the association is moderate 0,201. Chi-Square Tests (for the Table 5C) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 5,932 a 2,052,050 Likelihood Ratio 7,519 2,023,029 Fisher's Exact Test 6,762,029 Linear-by-Linear Association 4,588 b 1,032,041,027,017 N of Valid Cases 147 a. 1 cells (16,7%) have expected count less than 5. The minimum expected count is 2,07. b. The standardized statistic is -2,

22 Symmetric Measures (for the Table 5C) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,201,052,050 Cramer's V,201,052,050 N of Valid Cases PTW first collision contact code Table. 6 Number of accidents by severity related to: ROADSIDE OBSTACLES & PTW FIRST COLLISION CONTACT CODE PTW FIRST COLLISION CONTACT CODE severity of the accidents slight Guardrail barrier/posts injuries fencing serious injuries fatal structures/embankment/tree Parked vehicles/other unknown front centre rear other/ unknown/ no contact Count row % 75,0% 25,0% 100,0% Count row % 31,3% 55,4% 7,2% 6,0% 100,0% Count row % 63,9% 30,6% 2,8% 2,8% 100,0% Count Guardrail barrier/posts fencing structures/embankment/tree Parked vehicles/other unknown row % 43,3% 46,5% 5,5% 4,7% 100,0% Count row % 60,0% 40,0% 100,0% Count row % 25,0% 50,0% 8,3% 16,7% 100,0% Count row % 60,0% 40,0% 100,0% Count Guardrail barrier/posts fencing structures/embankment/tree Parked vehicles/other unknown row % 48,6% 43,2% 2,7% 5,4% 100,0% Count row % 50,0% 42,9% 7,1% 100,0% Count row % 77,8% 11,1% 11,1% 100,0% Count row % 66,7% 16,7% 16,7% 100,0% Count row % 62,1% 27,6% 3,4% 6,9% 100,0% 22

23 In the Table 6 we have analyzed the relationship between the motorcycle impact area and the. From Table 6A we can see that in about 90% of accidents the first collision contact has involved the front and the centre of the PTW; if we move from slight to fatal injuries there is an increment in the percentage of accidents for which the first impact has involved the front of the motorcycle (43,3% to 62,1%) whereas decrease the percentage of accidents for which the first impact has involved the centre of the motorcycle (46,5 to 27,6%). Only in a small number of accidents (especially for serious and fatal injuries) the first collision contact has been in the rear part of the PTW. Nevertheless the relationship between the two variables is not statistical significative (Fisher's Exact Test 4,667 p-value=0,571). Table. 6A Number of accidents related to: SEVERITY OF THE ACCIDENTS & PTW FIRST COLLISION CONTACT CODE PTW FIRST COLLISION CONTACT CODE severity of the accidents slight injuries Count front centre rear other/unkn own/no contact row % 43,3% 46,5% 5,5% 4,7% 100,0% serious injuries Count row % 48,6% 43,2% 2,7% 5,4% 100,0% fatal Count row % 62,1% 27,6% 3,4% 6,9% 100,0% Count row % 47,2% 43,0% 4,7% 5,2% 100,0% Chi-Square Tests (for the Table 6A) Asymp. Sig. Exact Sig. (2- Exact Sig. (1- Point Value df (2- Probability Pearson Chi-Square 4,552 a 6,602,613 Likelihood Ratio 4,704 6,582,686 Fisher's Exact Test 4,667,571 Linear-by-Linear Association 1,083 b 1,298,328,165,030 N of Valid Cases 193 a. 4 cells (33,3%) have expected count less than 5. The minimum expected count is 1,35. b. The standardized statistic is -1,

24 Symmetric Measures (for the Table 6A) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,154,602,613 Cramer's V,109,602,613 N of Valid Cases 193 Table. 6B Number of accidents related to: ROADSIDE OBSTACLES & PTW FIRST COLLISION CONTACT CODE PTW FIRST COLLISION CONTACT CODE Guardrail barrier/posts fencing Count structures/embankment/tree front centre rear other/unkn own/ no contact row % 59,4% 37,5% 3,1% 100,0% Count row % 34,6% 51,0% 7,7% 6,7% 100,0% Parked vehicles/other unknown Count row % 63,2% 31,6% 1,8% 3,5% 100,0% Count row % 47,2% 43,0% 4,7% 5,2% 100,0% In Table 6B we see that about the 60% of accidents, for which the has been the Guardrail barrier/ Post fencing, the first motorcycle impact has involved the front part. When the is structures/embankment/tree in 51% of accidents the PTW first collision part has been the centre. If we look the Fisher s Exact Test we find a statistical significative relationship (p-value=0,011). Chi-Square Tests (for the Table 6B) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 16,688 a 6,011,010 Likelihood Ratio 18,288 6,006,008 Fisher's Exact Test 15,325,011 Linear-by-Linear Association,664 b 1,415,454,228,039 N of Valid Cases 193 a. 5 cells (41,7%) have expected count less than 5. The minimum expected count is 1,49. b. The standardized statistic is -,

25 Symmetric Measures (for the Table 6B) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,294,011,010 Cramer's V,208,011,010 N of Valid Cases

26 2.4.2 Roadside & features of PTW rider kinematic of accident PTW rider number of impacts Table. 7 Number of accidents, by severity, related to: ROADSIDE OBSTACLES & PTW RIDER NUMBER OF IMPACTS PTW RIDER NUMBER OF IMPACTS severity of the accidents slight Guardrail barrier/ Posts fencing Count injuries row % 75,0% 25,0% 100,0% serious injuries fatal structures/embankment/tree Count row % 62,7% 25,3% 9,6% 2,4% 100,0% Parked vehicles/other unknown Count row % 80,6% 11,1% 8,3% 100,0% Count row % 68,5% 21,3% 8,7% 1,6% 100,0% Guardrail barrier/ Posts fencing Count structures/embankment/tree row % 10,0% 40,0% 30,0% 20,0% 100,0% Count row % 58,3% 16,7% 8,3% 16,7% 100,0% Parked vehicles/other unknown Count row % 66,7% 20,0% 13,3% 100,0% Count row % 48,6% 24,3% 16,2% 10,8% 100,0% Guardrail barrier/ Posts fencing Count structures/embankment/tree row % 50,0% 21,4% 21,4% 7,1% 100,0% Count row % 55,6% 22,2% 11,1% 11,1% 100,0% Parked vehicles/other unknown Count row % 66,7% 16,7% 16,7% 100,0% Count row % 55,2% 20,7% 13,8% 10,3% 100,0% In Table 7A we can see that in the 62,7% of accidents the rider sufferred only one impact, with the object which caused the injurie; inside the variable PTW rider number of impacts the percentages are inversely related with the number of impacts. We can appreciate that, for the serious and the fatal injuries, the amount of the category 3+ impacts (about 10%) is different respect to the same figure for the slight injuries (1,6%). The relationship between the severity of the accidents and the PTW rider number of impact is statistical significative: the Fisher Exact s Test is 12,169 which corresponds to an exact p-value of 0,042. The strength of association, Kendall's tau-c, is moderate 0,

27 Table. 7A Number of accidents related to: SEVERITY OF THE ACCIDENTS & PTW RIDER NUMBER OF IMPACTS severity of the accidents PTW RIDER NUMBER OF IMPACTS slight injuries Count row % 68,5% 21,3% 8,7% 1,6% 100,0% serious injuries Count row % 48,6% 24,3% 16,2% 10,8% 100,0% fatal Count row % 55,2% 20,7% 13,8% 10,3% 100,0% Count row % 62,7% 21,8% 10,9% 4,7% 100,0% Chi-Square Tests (for the Table 7A) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 11,624 a 6,071,068 Likelihood Ratio 11,169 6,083,110 Fisher's Exact Test 12,169,042 Linear-by-Linear Association 7,493 b 1,006,007,005,001 N of Valid Cases 193 a. 4 cells (33,3%) have expected count less than 5. The minimum expected count is 1,35. b. The standardized statistic is 2,

28 Symmetric Measures (for the Table 7A) Value Asymp. Std. Error a Approx. T b Approx. Sig. Exact Sig. Nominal by Nominal Phi,245,071,068 Cramer's V,174,071,068 Ordinal by Ordinal Kendall's tau-b,171,067 2,502,012,009 Kendall's tau-c,135,054 2,502,012,009 N of Valid Cases 193 a. Not assuming the null hypothesis. b. Using the asymptotic standard error assuming the null hypothesis. Table. 7B Number of accidents related to: ROADSIDE OBSTACLES & PTW RIDER NUMBER OF IMPACTS PTW RIDER NUMBER OF IMPACTS roadside Guardrail barrier/posts fencing Count structures/embankment/tree Parked vehicles/other unknown row % 43,8% 28,1% 18,8% 9,4% 100,0% Count row % 61,5% 24,0% 9,6% 4,8% 100,0% Count row % 75,4% 14,0% 8,8% 1,8% 100,0% Count row % 62,7% 21,8% 10,9% 4,7% 100,0% In Table. 7B we have put in relationship the with PTW rider number of impacts; the Guardrail barrier/posts fencing is the obstacle for which the PTW rider number of impacts accounts for the highest percentage in the categories above the two impacts. For the collision against the structures/embankment/tree the highest percentage of riders suffer only one impact. The Fisher's Exact Test of 10,509 with a p-value of 0,087 indicates that the relationship is no statistical significative, but it is not far from the threshold of 0,05. 28

29 Chi-Square Tests (for the Table 7B) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Value df Point Probability Pearson Chi-Square 10,507 a 6,105,102 Likelihood Ratio 10,477 6,106,135 Fisher's Exact Test 10,509,087 Linear-by-Linear Association 8,547 b 1,003,004,002,001 N of Valid Cases 193 a. 4 cells (33,3%) have expected count less than 5. The minimum expected count is 1,49. b. The standardized statistic is -2,924. Symmetric Measures (for the Table 7B) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,233,105,102 Cramer's V,165,105,102 N of Valid Cases

30 2.4.3 Roadside & features of roadside alignment Roadside horizontal alignment Table. 8 Number of accidents, by severity, related to: ROADSIDE OBSTACLES & ROADWAY HORIZONTAL ALIGNMENT severity of the accidents slight Guardrail barrier/posts injuries fencing serious injuries fatal structures/embankment/tree Parked vehicles/other unknown ROADWAY HORIZONTAL ALIGNMENT straight curve right curve left corner right corner left other Count row % 12,5% 25,0% 62,5% 100,0% Count row % 56,6% 18,1% 22,9% 1,2% 1,2% 100,0% Count row % 47,2% 22,2% 30,6% 100,0% Count Guardrail barrier/posts fencing structures/embankment/tree Parked vehicles/other unknown row % 51,2% 19,7% 27,6%,8%,8% 100,0% Count row % 40,0% 20,0% 40,0% 100,0% Count row % 25,0% 41,7% 33,3% 100,0% Count row % 40,0% 26,7% 33,3% 100,0% Count Guardrail barrier/posts fencing structures/embankment/tree Parked vehicles/other unknown row % 35,1% 29,7% 35,1% 100,0% Count row % 42,9% 14,3% 42,9% 100,0% Count row % 66,7% 11,1% 22,2% 100,0% Count row % 66,7% 16,7% 16,7% 100,0% Count row % 55,2% 13,8% 27,6% 3,4% 100,0% 30

31 Table. 8A Number of accidents related to: SEVERITY OF THE ACCIDENTS & ROADWAY HORIZONTAL ALIGNMENT severity of the accidents ROADWAY HORIZONTAL ALIGNMENT straight curve left curve right other slight injuries Count row % 51,2% 27,6% 19,7% 1,6% 100,0% serious injuries Count row % 35,1% 35,1% 29,7% 100,0% fatal Count row % 55,2% 27,6% 13,8% 3,4% 100,0% Count row % 48,7% 29,0% 20,7% 1,6% 100,0% From the marginal row of the Table 8A we see that about the 50% of accidents are happened in a straight road: if we compare the serious with the fatal injuries appears that for the serious both the straight and the curve left road have the highest percentage of 35,1% whereas for the fatal injuries the 55,2% of accidents have happened in a straight road and the 27,6% in a curve left road, in line with the general tendency. The relationship is no statistical significative how we can see from the Fisher s Exact test 5,921 p-value 0,387. Chi-Square Tests (for the Table 8A) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Point Value df Probability Pearson Chi-Square 5,829 a 6,443,435 Likelihood Ratio 6,259 6,395,428 Fisher's Exact Test 5,921,387 Linear-by-Linear Association,036 b 1,850,862,445,045 N of Valid Cases 193 a. 3 cells (25,0%) have expected count less than 5. The minimum expected count is,45. b. The standardized statistic is,189. Symmetric Measures (for the Table 8A) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,174,443,435 Cramer's V,123,443,435 N of Valid Cases

32 Table. 8B Number of accidents related to: ROADSIDE OBSTACLES & ROADWAY HORIZONTAL ALIGNMENT ROADWAY HORIZONTAL ALIGNMENT roadside straight curve left curve right other Guardrail barrier/posts fencing Count structures/embankment/tree row % 34,4% 46,9% 18,8% 100,0% Count row % 53,8% 24,0% 20,2% 1,9% 100,0% Parked vehicles/other unknown Count row % 47,4% 28,1% 22,8% 1,8% 100,0% Count row % 48,7% 29,0% 20,7% 1,6% 100,0% We notice, from Table 8B, that the curve left is the type of road alignment which have characterized the highest percentage (46,9%) of impacts against the Guardrail barrier/posts fencing obstacle; whereas for the other types of, the roadway horizontal alignment category which have characterized the highest percentage of accidents is the straight road. The relationship between the variables is no statistical significative Fisher s Exact Test 6,697 p- value 0,311. Chi-Square Tests (for the Table 8B) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Value df Point Probability Pearson Chi-Square 7,154 a 6,307,306 Likelihood Ratio 7,278 6,296,344 Fisher's Exact Test 6,697,311 Linear-by-Linear Association,010 b 1,919,949,485,051 N of Valid Cases 193 a. 3 cells (25,0%) have expected count less than 5. The minimum expected count is,50. b. The standardized statistic is -,101. Symmetric Measures (for the Table 8B) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,193,307,306 Cramer's V,136,307,306 N of Valid Cases

33 2.4.4 Roadside infrastructure & accident causation Roadside condition and defects Table. 9 Number of accidents, by severity, related to: ROADSIDE OBSTACLES & ROADSIDE CONDITION AND DEFECTS ROADSIDE CONDITION AND DEFECTS severity of the accidents none other slight Guardrail barrier/posts fencing Count injuries row % 50,0% 50,0% 100,0% serious injuries fatal structures/embankment/tree Count row % 63,9% 36,1% 100,0% Parked vehicles/other unknown Count row % 61,1% 38,9% 100,0% Count row % 62,2% 37,8% 100,0% Guardrail barrier/posts fencing Count row % 80,0% 20,0% 100,0% structures/embankment/tree Count row % 83,3% 16,7% 100,0% Parked vehicles/other unknown Count row % 73,3% 26,7% 100,0% Count row % 78,4% 21,6% 100,0% Guardrail barrier/posts fencing Count row % 64,3% 35,7% 100,0% structures/embankment/tree Count row % 66,7% 33,3% 100,0% Parked vehicles/other unknown Count row % 83,3% 16,7% 100,0% Count row % 69,0% 31,0% 100,0% From the marginal row of Table 9A appears that in the 66,3% of accidents the roadside don t present defects; the percentages are differented passing by serious to fatal injuries: for the serious injuries in the 78,4% of cases the roadside don t present defect whereas for fatal injuries the same figure decrease about ten percentage points. The relationship between the variables is no statistical significative (Pearson Chi-Square 3,462 p-value=0,177). 33

34 Table. 9A Number of accidents related to: SEVERITY OF THE ACCIDENTS & ROADSIDE CONDITION AND DEFECTS ROADSIDE CONDITION AND DEFECTS severity of the accidents none other slight injuries Count row % 62,2% 37,8% 100,0% serious injuries Count row % 78,4% 21,6% 100,0% fatal Count row % 69,0% 31,0% 100,0% Count row % 66,3% 33,7% 100,0% Chi-Square Tests (for the Table 9A) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Value df Point Probability Pearson Chi-Square 3,462 a 2,177,172 Likelihood Ratio 3,635 2,162,159 Fisher's Exact Test 3,412,177 Linear-by-Linear Association 1,507 b 1,220,260,130,039 N of Valid Cases 193 a. 0 cells (,0%) have expected count less than 5. The minimum expected count is 9,77. b. The standardized statistic is -1,227. Symmetric Measures (for the Table 9A) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,134,177,172 Cramer's V,134,177,172 N of Valid Cases

35 Table. 9B Number of accidents related to: ROADSIDE OBSTACLE & ROADSIDE CONDITION AND DEFECTS roadside ROADSIDE CONDITION AND DEFECTS none other Guardrail barrier/posts fencing Count row % 65,6% 34,4% 100,0% structures/embankment/tree Count row % 66,3% 33,7% 100,0% Parked vehicles/other unknown Count row % 66,7% 33,3% 100,0% Count row % 66,3% 33,7% 100,0% We find a very similar percentage distribution between the different (Table. 9B) with values close to the marginal row. The relationship, even in this case, between the variables is no statistical significative and the p-value is closed to 1. Chi-Square Tests (for the Table 9B) Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- Value df Point Probability Pearson Chi-Square,010 a 2,995 1,000 Likelihood Ratio,010 2,995 1,000 Fisher's Exact Test,045 1,000 Linear-by-Linear Association,009 b 1,924 1,000,507,090 N of Valid Cases 193 a. 0 cells (,0%) have expected count less than 5. The minimum expected count is 10,78. b. The standardized statistic is -,096. Symmetric Measures (for the Table 9B) Value Approx. Sig. Exact Sig. Nominal by Nominal Phi,007,995 1,000 Cramer's V,007,995 1,000 N of Valid Cases